Cutting edge of air-quality science: collecting cows' pungent gases

An orange balloon floated 50 feet above California State University, Fresno's small dairy herd last week, helping in the unsavory task of gathering air samples from a plume of pungent gases.

On the ground, a gas chamber held more samples while massive Holstein and Jersey cows drooled and munched feed nearby. Researchers sweated in the barnyard stench, making sure sampling instruments worked properly.

It's not glamorous, but this is the cutting edge of air-quality science. In just the last decade, dairies have emerged as a serious source of air pollution, and there's work to do.

Fresno State is among 10 universities around the country studying every angle of the gases coming from the multibillion-dollar industry. What chemicals are in them? What can be done to limit them?

For good reason, the scientists at Fresno State are among the research leaders. The San Joaquin Valley is the nation's most productive dairy region, with about 2 million milking cows